1. Field of the Invention
The invention relates to a method for matching an actual characteristic curve or an actual characteristic diagram that characterizes the operating mode of a hydrodynamic component to a set characteristic curve or a set characteristic diagram that has been pre-defined or can be given in advance during the final test of the hydrodynamic component.
2. Description of Related Art
As a rule, hydrodynamic components are subjected to a final test during fabrication, in which, on the test stand, the characteristic diagram adjustable with it is measured and is stored as a fixed characteristic curve. During this process, as a rule, a predetermined set value is established by customer specification and all hydrodynamic components of the same design type should lie in a certain tolerance band within these set value specifications. The actual values that have been currently attained with the hydrodynamic component are measured and stored as a characteristic curve. In the event of very strong deviations between the attained actual values and the desired set values, structural measures for subsequent processing are implemented; for a hydrodynamic retarder, for example, these may involve an enlargement of the outlet bore. However, through the predetermination of the tolerance band, it is often the case that the theoretical braking power that is fully available is not at all exhausted. Accordingly, in the case of hydrodynamic retarders of the same type, the same actuation results in different braking torques being attainable.
In order to compensate for ageing effects in fabrication spreads, it has been known—for example, for optimizing the shifting operation in vehicle transmissions, particularly automatic transmissions of vehicles—to design these transmissions with an adaptive control. Here, electrohydraulically actuated friction elements bring about the shifting between the various gear-ratio steps. An actual variable that characterizes the shifting operation (preferably the slip time, the shifting time, or the rpm gradient during the slip time) is compared with a stored set variable and, when a pre-given deviation is exceeded, a correction value is stored. The latter then acts during subsequent shifting operations in a corrective manner in terms of an adaptive control on the creation of a control variable for the friction elements, preferably the hydraulic pressure. This process is characterized in that the adaptive control occurs only during operation and thus an adjustment is possible only after a certain operating time.
Previously known from EP 1 437 520 A2 for hydrodynamic components in the form of hydrodynamic couplings is a method for controlling an automatically actuated coupling, in which the torque that is to be transmitted is controlled according to a coupling characteristic curve as a function of the coupling position and the coupling characteristic curve is corrected so as to compensate for changes in the coupling behavior. The coupling characteristic curve is adapted to this end, for which purpose a minimally allowable characteristic curve and a maximally allowable characteristic curve are generated and the valid coupling characteristic curve in the form of an interpolated characteristic curve, which is adapted to the coupling behavior according to the control variables, is calculated by interpolation between the values of the minimal characteristic curve and those of the maximal characteristic curve. This kind of regulation results in a response to changes in the coupling properties due to various influencing factors.
Methods for controlling hydrodynamic components during operation have been further previously known from DE 106 45 443 C2 and DE 33 35 259. In these designs, the matching of the actual value to the set value occurs through regulation during operation.